Katie Hennessy

Salmonella — Cause or Consequence?

An adult horse with diarrhea can be a real headache. Not only is it messy but it means your horse’s intestinal track is not feeling well. Diarrhea can cause cramping and other signs of colic. Diarrhea in adult horses can have several causes and consequences but one issue that can be both is Salmonella. It is difficult to determine if the Salmonellosis came before or after the diarrhea started but caution and supportive care is critical.

Before the diarrhea, when your horse seems fine, they can carry salmonella in their gut. There is no evidence that they’re infected with such a nasty bacterium until they are stressed and become a fecal shedder of the Salmonella spp. Horses that have had a history of colic or diarrhea are at increased risk of shedding with stress being a major contributor to cause shedding in normal horses. While a healthy horse can carry Salmonella in their gut, not all horses do and can become sick when they come in contact with the bacteria and are infected. 

Salmonellosis causes diarrhea in horses, other animals and humans so we want to minimize the risk of spreading and infecting others. Your veterinarian can diagnose salmonella with a fecal culture from give samples collected over several days; this is because the bacterium is only shed intermittently in feces. Similarly, if your horse has been ill with diarrhea, a negative Salmonella culture confirms that your horse is clear of the disease. 

Before your diagnosis, remember that the bacteria is spread through manure, so it is important to practice cleanliness and limit exposure of any horse with diarrhea. Some tips to protect yourself, your horses and others is to avoid stress for your horse, prevent other horses from coming into contact with your horse’s feces (use separate tools and paddocks), wear disposable gloves, wash your hands frequently and prevent your horse from being in contact with children or people that are immunocompromised while shedding (up to 6 weeks after an episode of diarrhea).

If you have any questions or concerns, talk with your veterinarian.

BIO: Dr. Katie Hennessy graduated from the University of Illinois College of Veterinary Medicine in 2008 with a degree in large animal health and equine medicine. She completed an advanced internship at The Equine Medical Center of Ocala and is currently the owner and practicing veterinarian at Polk Equine. Her expertise ranges from small and exotic creatures to large animals, specializing in equine medicine.